Pallet stacking device



March 1965 A. c. FARLEY ETAL 3,

PALLET STACKING DEVICE Filed May 8, 1961 4 Sheets-Sheet l a A a: en r March 9, 1965 A. c. FARLEY ETAL PALLET STACKING DEVICE Filed May 8, 1961 4 Sheets-Sheet 2 March 9, 1965 A. c. FARLEY ETAL 3,172,375

PALLET STACKING DEVICE 4 Sheets-Sheet 3 Filed May 8, 1961 TOR "iz r March 1965 A. c. FARLEY ETAL 3,172,375

PALLET STACKING DEVICE Filed May 8, 1961 4 Sheets-Sheet 4 36 7. 52 {Z L1 AL;

5 Maz'e er United States Patent 3,172,375 PALLET STACKING DEVICE Arthur C. Farley, Philadelphia, and Allen E. Michener,

Hillside Estate, Horsham, Ra, assignors to Artco Corporation, Hatfield, Pin, a corporation of Pennsylvania Filed May 8, 1961, Ser. No. 168,369 18 'Claims. (Cl. 108-53) The present invention relates to pallet stacking devices of the character which may be employed in warehouses, depots, and the like, to permit placement of pallets in a column arrangement one on top of another.

The present application is a continuation-impart of our co-pending application Serial No. 67,395, filed November 4, 1960, and now abandoned, for Pallet Stacking Device.

A purpose of the invention is to provide a bearing support for an upper pallet in a pallet stacking device which will support both ends of the side stringers and both ends of the middle stringer of said pallet.

A further purpose is to prevent warpage and sagging even with concentration of load non-centrally, as at one side, at the front or at the back of the upper pallet.

A further purpose is to support all three stringers of the upper pallet completely from the horizontal frame.

A further purpose is to better resist lateral separation of the parts of a pallet stacking device by interlocking of interconnections.

A further purpose is to produce a pallet stacking device which will more effectively resist torsion.

A further purpose is to make a pallet stacking device stronger from the standpoint of beam loading.

A further purpose is to permit location of the interconnecting devices transverse to the side thrust.

A further purpose is to permit stacking of the components of the device in a smaller space.

A further purpose is to reduce torsional vibration of the device of the invention.

A further purpose is to make the uprights separable from the top frame at the corners while having the top frame of a single welded unit.

A- further purpose is to employ cross braces for the uprights, which may either permanently connect the uprights or removably interconnect the uprights.

Further purposes appear in the specification and in the claims.

In the drawings we have chosen to illustrate a few only of the numerous embodiments in which the invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a perspective showing the pallet stacking device in place on a pallet and ready to receive an upper pallet.

FIGURE 2 is a perspective showing the opposed halves of the pallet stacking device in position, for example, prior to installation on a pallet.

FIGURE 3 is an exploded perspective showing the assembled pallet stacking device in position to lower and interconnect with a pallet.

FIGURE 4 is a top plan view of a modification of the device of FIGURES 1 to 3, in which the shape of the horizontal rectangle has been changed, and illustrating the angular disposition of the horizontal rectangle with respect to the uprights and the feet.

FIGURE 5 is a perspective of half a modified pallet stacking device which has feet without interconnect-ions.

FIGURE 6 is an exploded perspective of a modification of the device of the invention.

FIGURE 7 is a fragmentary perspective of a variation in the side frame of'the device of FIGURE 6.

FIGURE 8 is a perspective of a further variation in 3,l72,375 Patented Mar. 9, 1965 the side frame of the device of FIGURE 6, having removable top and bottom braces.

FIGURE 9 is a fragmentary side elevation partly in axial section of a further variation in the side frame, using a removable diagonal brace.

FIGURE 10 is a fragmentary top plan view of the interconnection between one of the uprights and the diagonal brace in FIGURE 9.

Describing in illustration but not in limitation and referring to the drawings:

Extensive use is being made in warehouses and depots of multiple part pallet stacking by means of pallet stacking devices which permit placing of an upper pallet above a lower pallet. Frequently such columns are assembled three pallets high.

Such pallet stacking devices are desirably disassembled when not in use, and therefore they are frequently made to separate into components which can be readily nested or stored.

It is important, however, that the pallet stacking device when assembled be capable of withstanding not only the normal static loads of the pallet which may be rest ing on it and the pallet which may be above that, but also the occasional unexpected or unpredictable loading, which may be due to improper operation of the fork lift truck, or due to application of lateral components from an adjoining storage location against the pallet or the pallet stacking device.

Another diificulty which has been encountered in the art is that some of the pallet stacking devices do not thoroughly support all stringers of the upper pallet at both ends, but rely upon transfer of load through the deck boards to prevent sagging or deformation of the upper pallet.

A further serious ditliculty encountered in the art has been that some of the separable pallet stacking devices are readily and unintentionally separated during service, causing collapse of the structure.

The present invention is concerned particularly with making a pallet stacking device which will be structurally stronger under stack loading and more capable of resisting impacts by vehicles and products being loaded or removed.

The device of the invention supports the front and the back of the side stringers and also of the middle stringer of the upper pallet, so that off-center loading of said upper pallet will not be objectionable.

The device of the invention also provides a rigid welded box frame which effectively resists torsion.

The pallet stacking device of the invention offers an interlock feature which tends to prevent separation of the halves due to the fact that one of the components of the separating force tends to lock the interconnections together, yet assembly is easily made.

On actual test as compared with previous pallet stacking devices which have tended to have had an interconnection near the center of the pallet space, it has been found that the device of the invention is very markedly stronger.

A desirable feature of the invention is that the feet interlock with the side stringers of the lower pallet and tend to prevent lateral separation. Weight on the pallet stacking device also tightens the locking to the stringers. The device may be used with separate feet or interconnected feet. Where separate feet are employed, the pallet stacking device may be placed with the elements of the top horizontal frame which are separable disposed generally in a direction parallel to the stringers so as to further impede separation.

The device of the invention can be adapted to unusual heights of load and unusual sizes or shapes of pallets as desired.

r) In some cases it is very important to have close packing of the units to reduce shipping and storage costs. Some of the forms of the device of the invention are particularly favorable for this purpose.

welded top frame also is desirably applied to the up rights by sockets at the corners of the frame which engage and stiffen the uprights.

Considering now the drawings in detail, we there illustrate a bottom pallet 2% having longitudinal side stringers 21, a longitudinal middle stringer 22, transverse bottom boards 23 and transverse deck boards 24 as well known. See FIGURES 1 to 3, inclusive. In the space between the side and the middle stringers and between the bottom boards and the deck boards the fork element of a fork lift truck can be inserted to manipulate the pallet.

Mounted on top of the pallet is a pallet stacking device 25 suitably constructed of steel, and including four upright or posts 26 conveniently made from steel pipe and arranged in quadrature so that they may suitably be placed at the four corners of the pallet or at other suitable quadrature locations on the pallet as well known. At the bottom, each upright 26 is interconnected with a foot 27, described more in detail later, adapted to rest upon and anchor to the pallet.

At the top in horizontal relation is placed a rectangular frame 28 which will vary in shape depending upon the relative proportions of the pallet, the form of FIG- URES 1, 2 and 3 illustrating sides which are unequal while in the form of FIGURE 4- the sides are essentially equal and the rectangle is generally a square.

The horizontal frame consists of opposed parallel sides 30 which are integral and may suitably be made of steel pipe or other suitable structural members and opposed opposite parallel sides 31 which in one embodiment are separated, each consisting of a side half or portion 32, suitably a steel pipe or other structural member, which abuts against and interconnects with a side portion or half 33, likewise suitably of pipe or other structural member. The interconnection desirably takes the form of a pin 34 which protrudes from the half 32 and enters a socket 35 in the end of the half 33. Where the relation of the pins and sockets are staggered, it will be evident that the L-shaped halves of the pallet stacking device can be identical as shown.

The pin extends in the axial direction of the half 32 and the socket is axial as shown, and the pin desirably closely engages the socket so as to impede unintended separation of the parts as later explained.

Each of the halves 30 has extending in prolongation from it at one end an extension 36 which in the preferred embodiment is secured as by welding to the top of one of the uprights 26. In addition, the sides of the rectangular horizontal frame 23 are connected to one another as by welding at the corners.

The lengths of the extensions 36 and 37 are relatively short with respect to the lengths of the sides of the rectangular horizontal frame, preferably being of the order of 5 to 22% and most desirably about 10%, so that the sides of the horizontal frame are disposed at a relatively small angle with respect to the line connecting the vertical centers of the adjoining uprights.

Each of the feet 27 at the bottom of the uprights is preferably produced by an angle 38 which has a vertical side 40 along the outside of the side stringers and which has a horizontal flange 41 which rests on the top of the deck boards. At positions corresponding to the spaces between deck boards, a projection 42 lanced from the horizontal flange 41 protrudes down between two deck boards and behind the side stringer and as best seen in FIGURE 5 has at the side adjoining the stringer a wedge surface 43 which tends to grip and bite into the stringer and hold the foot locked against moving outwardly as well as slipping longitudinally of the stringer.

In the preferred embodiment, the feet 27 are interconnected by a portion 44 of the angle which extends longitudinally of the side stringer, although in the form of FIGURE 5 no such interconnection between the feet is provided.

In order to assemble the device on a pallet, the pin connect ors of the halves 32 and 33 are moved longitudinally of the sides until they interengage as shown by FIGURE 2 and then the assembled structure is lowered on to the pallet as shown in FIGURE 3 until it achieves the position of FIGURE 1 with the projections 42 wedged between the deck boards and behind the stringers.

This assembly can be accomplished before or after the lower pallet is loaded.

The operator can then deposit another pallet on top. It will then be evident that the side stringers of the upper pallet will extend across and be supported by a half 32 at one side of the front and the extension 37 at the other side of the front and by an extension 37 at one side of the rear and a side 32 at the other side of the rear. If there is any lateral misalignment, the side stringers will be supported by the fact that they will cross the side elements 30 of the top frame. Thus, there is front and back support of the side stringers notwithstanding that the upper pallet is not precisely positioned laterally.

In the case of the middle stringer, it will be supported at the front and back by the front and back portions of the horizontal frame which are widely separated and therefore will not permit it to rock or sag.

Thus, there is excellent bearing support for the upper pallet which will guard against warpage and sagging even with concentration of loadon the upper pallet at one side or at the back and front.

The construction of the present invention is extremely sturdy and constitutes in effect a welded box frame, so that torsional loads, such as might be imparted by collision of a vehicle with one of the columns, will be effectively resisted; All joints are made approximately at right angles or approximately perpendicularly, thus making welding and nibbling in preparation for Welding easier.

In experiments on a 48" x 48" pallet provided with a pallet stacking device of the invention, where a pallet load was placed on top, it was found that the force required to separate the two pallet halves at the pin and socket joints by side thrust at the top was 1100 pounds. This is due to the fact that when the side thrust was applied at adirection parallel to the axis of the deck boards, one of the components of the side thrust tended to urge the pins laterally and make them bind in or interlock with the sides, and this therefore causes resistance to separation. This component is the one transverse to the axis of the pin.

The pallet stacking device was tested by loading the upper pallet, regarding the horizontal frame as a beam. As compared with a previous widely used commercial device, it was found that the ability to withstand beam loading was increased by 50%.

The full angle foot interconnection as shown in the form of FIGURES 1 to 4 inclusive, provides a very rigid assembly, and the interconnection with the pallet at the foot is undoubtedly one factor in resisting separation of the halves of the stacking device. The tapering surface 43 on the projection at thefoot which grips the inside of the side stringer 21 also serves to wedge the foot tight against the pallet.

In FIGURE 5 we illustrate a modified form which can be used in the manner as shown for FIGURES 1 to 4, or, with wide enough separation between the foot, flange sa /gays 5 40 and the projection surface 43 can be placed in 90 relation, with the feet at the front and back of the pallet instead of the sides. When used in this latter manner the pin and socket joints extend generally longitudinally rather than transversely, and this further serves to resist against separation due to lateral pull.

It will also be evident that in the form of FIGURE 5 the feet can be placed at the middle of each side of the pallet with appropriate fitting to the deck board or the stringer as the case may be.

The form of FIGURE 5 is therefore very suitable where there is effective side thrust.

The form of FIGURE 5 is also very suitable for wide varieties of different shapes and contours of pallets and different heights of loads.

In many cases it is preferable to use a rigid welded top frame Without any separation within itself, which is separable from the side frames as shown in FIGURE 6. This form is preferred. In this form the sides 31 are integral instead of being separated. Each extension 36 or 37, as the case may be, has welded to it at the outer end at 45 a connector, suitably a downwardly extending socket 46 on the center line of each upright 26, which receives and telescopes with the upper end of the appropriate upright 26. The construction of the feet at the bottom can be the same as that of FIGURES 1 to 4 inclusive.

In the form of FIGURE 6 the side frames have near the top of the uprights just below the sockets 46 cross braces 47 which hold the upper ends of the uprights 26 precisely spaced so that they cannot readily bend and interfere with entry into the sockets 46.

The cross braces 4'7 serve also to prevent the load from falling outwardly, and this function is aided by vertical retaining bars 48 which extend from the foot portion 44 vertically to connect with the cross brace 47 at the top. It will also be evident that bars 48 can be located at the front and back as well as atthe sides, in order to retain the loads.

The structure of FIGURE 6 disassembles into three elements, one of which is the top frame and two of which are side frames and these stack or pile very compactly. Thus the space in a truck which will pack 100 units of the character of the form of FIGURE 1 will pack approximately 250 units of the form of FIG- URE 6. This is an important aspect, since on the average shipping cost is of the order of 15% of the overall cost of a pallet stacking device.

One of the great advantages of the form of FIGURE 6 is that since the top frame is made in one piece it is very resistant against torsion on a vertical axis. There has been a tendency when pallet stacking devices are stacked several pallets high for the stack to vibrate torsionally sometimes for several minutes after the last pallet and load are applied. This torsional vibration is quite objectionable and the form of FIGURE 6 of the present invention is very resistant against torsional vibration. This is a matter of importance particularly in heavy duty high stacking installations.

The extension of the sockets 46 over the end of the uprights, with relatively close engagement of the uprights by the sockets, tends to stiffen the uprights as columns and effectively shortens the unsupported length of the columns, making the structure stronger against load applied on the upper pallet and particularly against eccentric loading which places a large part of the load on one corner.

One of the difficulties encountered in pallet stacking devices is that careless operation of the fork lift truck may apply impact loads to the pallet stacking device, and impact loads are also applied when the load on an adjoining pallet shifts. The all-welded top frame of FIGURE 6 and the socket arrangement increases the resistance against torque which might be applied laterally or diagonally fore increases the resistance to the side frame, and ther to impact loading.

In some cases the load on the pallet itself tends to apply force laterally to the side frames, and in the form of FIG- URE l in an extreme case this may tend to separate the pin and socket connections at 34 and 35'. In the form of FIGURE 6 however there is great resistance against any lateral separation since the sockets strongly brace the upper ends of the uprights against moving laterally.

The arrangement of the sides 3t? and 31 of the top frame assures that four point bearing will be obtained on the top pallet even though the Operator of the fork lift truck does not insert the top pallet exactly centrally.

Some difficulty has been encountered with the device of FIGURES 1 to 5 due to careless piling and handling when the halves of the frame are disassembled. This has caused bending of the portions 32 and 33 so that they are not truly parallel, and it is then difficult to make the pin and socket connection without taking the trouble to straighten the portions 32 and 33.

In the form of FIGURE 6 this is not likely to happen because the cross brace 47 is located close to the top of the uprights and braces them very Well against distortion.

In some instances the cross brace 47 may be omitted along with the vertical retaining bars 48 of the side frame. This is shown in FIGURE 7 where the uprights are not cross connected at the top until the top frame is installed as in FIGURE 6.

If desired, separate foot portions may be employed as in FIGURE 5, to produce the side frames of FIGURE 6. This is shown in FIGURE 7, where the feet and uprights are separate. The uprights in this instance can also be provided with removable cross braces and this is shown in FIGURES 8, 9 and 10.

In FIGURE 8 the cross brace 47' is removably fastened at the ends to the uprights by straps 56 secured by bolts 51. In this instance a lower cross brace 47 is located near the feet and this is secured by similar straps S0 and bolts 51. The two cross braces 4'7 and 47 are interconnected by vertical retaining bars 18.

The form of FIGURE 8 has the same advantage as that of FIGURE 6 in tending to retain the load against moving sideways and of course it will be evident that the projections 42 at the feet prevent the side frames from moving outward at the bottom. It will furthermore be evident that in the form of FIGURE 8, if an individual upright is damaged as by the fork lift truck, another component can be salvaged by inserting a new upright. The same is true if a cross brace or cross braces are damaged, in which case a new cross brace assembly can be inserted.

In some cases as shown in FIGURES 9 and 10 a diagonal cross brace 47 is used which engages near the top of one upright and near the bottom of another upright of the pair, using straps 56' secured by bolts 51'. This like the other cross braces retains the uprights against moving toward and away from one another and restrains the load against moving laterally.

All of the forms of the invention can be used. with abnormal height for light loads, or with increased strength of the structural elements, they can be employed in usual sizes for heavy loads.

Inasmuch as the angle flange 49 is deep enough to extend along the outer edges of the side stringer, openings 52 are provided as shown in FIGURE 6 to receive screws or bolts which will interconnect to the side stringer, making the pallet stacking frame a permanent fixture on the pallet. Similar openings are shown in FIGURE 9.

In View of our invention and disclosure, Variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the structure shown, and we, therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. In a pallet stacking device, four uprights arranged so that their centers at the bases thereof when viewed in plan form the corners of a rectangle, a horizontal frame of rectangular form when viewed in plan located at the top of the uprights but itself spaced from the individual uprights, the center lines of all sides of the frame lying in a single horizontal plane and the center lines of the sides each, when viewed in plan, being located at least mostly toward the inside of the rectangle formed by the centers of the uprights but being throughout at least substantially all its length closer to the sides of that rectangle than to the center of that rectangle, and horizontal extensions from the perimeter of said horizontal frame to the uprights, said uprights terminating in upward extension at a point no higher than the top surface of the horizontal frame.

2. A device of claim 1, in which said extensions interconnect with the corners of said horizontal frame.

3. A device of claim 1, .in which each extension is located in direct prolongation of one of the sides of the rectangular frame.

4. A device of claim 1, in which each side of thereotangular frame is angularly disposed with respect to the line interconnecting the nearest two of the uprights.

5. A device of claim 1, in which each extension is located in direct prolongation of one of the sides of the rectangular frame, and each side of the rectangular frame is angularly disposed with respect to the line interconnecting the nearest two of the uprights.

6. A device of claim 1, in which said extension has a length between and 22% of the length of the adjoining side of said rectangular frame.

7. A device of claim 1,- having on generally transversely extending sides of said rectangular horizontal frame, interconnections which permit transverse separa tion of said device into two parts. 7

8. A device of claim 7, in which the interconnections comprise pin and socket elements which are disposed at an angle to the line connecting the nearest of the two uprights, whereby separation of the intcrco'nnections'is retarded by creation of a lateral binding force component.

9. 'A device of claim 1, in which the rectangle has corners, and interconnections at the top of the corners connect the uprights with the horizontal frame.

' 10. A device of claim 9, in which the interconnections comprise sockets on the extensions from the horizontal frame which receive the uprights.

11. A device of claim 9, in which the uprights areconnected by a cross brace near their upper ends.

12. A device of claim 11, in which the cross brace is connected with vertical elements between the uprights.

13. A device of claim 11, in which the cross brace has removable connections at the ends of the cross brace.

14. A device of claim 9, in which the cross brace is connected at the top to one upright and at the bottom to the other upright of each pair.

the bottonrof the uprights adapted to interengage with the pallet and anchor the uprights against movement with respect to the pallet.

16. In a demountable' pallet stacking device, four vertical posts forming the corners of a first rectangle in their horizontal positioning, and a frame on top of the tops of the posts, said frame being made up of four straight arms in the same horizontal plane, each of which extends from a position on top of a different one of the posts to a position along an adjacent one of the other arms spaced from the nearest there of the posts, the:arms being attached together at said respective positions spaced from the posts and forming, by said attachments and the portions of the arms away from the posts from said attachments, a second rectangle which in its positioning from the horizontal standpoint is inside of, spaced from all sides of, and skewed with relation to, the'first rectangle formed by the positions of the posts.

17. A pallet stacking device comprising four vertical posts located at the corners of a first rectangle when viewed in plan, a horizontal frame mounted on the tops of the posts and made up of straight tubes each of which runs from the top of one post to end at a point where it is attached to another of such straighttubes about 10 percent of the way along on the other tube between where that other tube is at the top of another post and where it ends at still another tube, and toward but substantially spaced from the top of that other post, the center lines of the tubes through all their joining points forming a second rectangle when viewed in plan which as thus .viewed is entirely insideof the first'rectangle and skewed therefrom, and is located entirely in the same horizontal plane above the tops of the posts, and base members for supporting the posts in a fixed position on a pallet.

18. Apallet stacking device of claim 17, in which the horizontal frame is separably mounted on the posts by means of sockets affixed to and extending down from the bottom of the horizontal frame, into which sockets the tops of the posts fit. 1

References Cited by the Examiner UNITED STATES PATENTS 1,235,332 7/17 Lachman 189-12 2,791,325 5/57 Schecter 248-420 2,828,932 4/58 De Pew 248--- 2,924,339 I 2/60 Skubic 10853 2,932,477 4/60 Franks 10853 2,936,984 5/60 Skubic 10853 2,953,340 9/60 Skubic 248.120 2,969,948 1/61 Higgins z 248-120 2,988,313 6/61 Ellison 248120 3,000,602 9/61 OBrien 248-120 FOREIGN PATENTS 1,211,888 3/60 France.

FRANK B. SHERRY, Primary Examiner. V

CLAUDE A. LE ROY, ROBERT C. RIORDON,

Examiners. 

1. IN A PALLET STACKING DEVICE, FOUR UPRIGHTS ARRANGED SO THAT THEIR CENTERS AT THE BASE THEREOF WHEN VIEWED IN PLAN FORM THE CORNERS OF A RECTANGLE, A HORIZONTAL FRAME OF RECTANGULAR FORM WHEN VIEWED IN PLAN LOCATED AT THE TOP OF THE UPRIGHTS BUT ITSELF SPACED FROM THE INDIVIDUAL UPRIGHTS, THE CENTER LINES OF ALL SIDES OF THE FRAME LYING IN A SINGLE HORIZONTAL PLANE AND THE CENTER LINES OF THE SIDES EACH, WHEN VIEWED IN PLAN, BEING LOCATED AT LEAST MOSTLY TOWARD THE INSIDE OF THE RECTANGLE FORMED BY THE CENTERS OF THE UPRIGHTS BUT BEING THROUGHOUT AT LEAST SUB- 